1. Field of the Invention
The present invention relates to an objective oberservation optical material capable of screening ultraviolet rays and correcting such defects of vision as nearsightedness, farsightedness, astigmatism and presbyopia.
2. Description of the Prior Art
In the past, generally the incidence of ultraviolet rays to the eyes has been prevented by the use of glasses made by providing parallel-surface glasses or plastic pieces with suitable light screening properties and/or absorbing properties with respect to specific wavelengths by adding a light screening or absorbing substance during their raw material stage, coloring the transparent glasses or applying a coating to the surface of the glasses, i.e., so-called sunglasses and in the case of the wearer having nearsightedness, farsightedness, astigmatism or presbyopia the glasses have consisted of lenses or other glasses have been worn on the sunglasses for correcting the defect of vision.
However, such sunglasses are expensive and often they are not used habitually thus requiring the provision of a case for carrying or accommodating the glasses. Also, in everyday life or when going out, particulary or for protection from the intense sunshine in the summer, the sunshine on a snowy day or the reflected light of such sunshine, it is necessary to use a more powerful ultraviolet screening substitute for glasses in place of the sunglasses and the same applies to any person having nearsightedness farsightedness, astigmatism or presbyopia.